Could an additional Ethernet Port for outgoing connection be added so that these controllers could be configured in an EtherCAT chain? This would unlock an entirely new branch of applications using the same protocol and control schemes that many Industries use.

I checked the W5500 Ethernet controller datasheet and I think that it's able to support up to 8 sockets. So to me, that means the only major complication would be finding physical space in the design for the port.